Infectious Diseases is a medical specialty devoted to diagnosis, treatment and prevention of infections. Infections are illnesses caused by tiny living organisms or "germs" such as bacteria, viruses, fungi and parasites. Our environment is teaming with germs, including many that live harmlessly on or in our bodies. Some germs, such as bacteria in our intestinal tracts, are even beneficial to our health -- as long as their numbers stay in the normal range.

An infection occurs when a germ overcomes the body's natural defenses (immune system), which allows the germ to multiply inside or on the surface of the body and cause illness. Germs can gain entry in many ways. A person can become infected by touching a contaminated surface, swallowing contaminated water or food, breathing in germ droplets in the air, getting a bite from an infected insect or animal, or having close physical contact with an infected person (e.g., kissing, sexual contact).

Once a germ begins to multiply and cause illness, the symptoms, severity, and duration of the illness vary depending on the germ causing the infection and other factors, such as a person's age, overall health, and immune system response. For example, compared with healthy people, those with conditions that weaken the immune system (for example, people with cancer being treated with chemotherapy) not only are at greater risk for infections, the infections can be more severe or more difficult to treat. But even in healthy people, infections vary greatly depending on the cause. They can range from mild to life threatening; last a week, a month, or many years; and affect one area of the body (e.g., pneumonia [lungs], sinusitis [sinuses], cystitis [bladder]) or the entire body (e.g., AIDS).

Many infections are preventable with measures to avoid the spread or multiplication of germs or with the use of vaccines. Even when infection occurs, it often is possible to eliminate or control the bug. Some infections do not even need treatment. For example, the common cold virus usually is cleared from the body in a matter of days if a person's immune system is working properly. On the other end of the spectrum is HIV infection (the cause of AIDS), which can last the rest of a person's life and require long-term treatment with combinations of drugs to keep the virus under control. And although bacterial and fungal infections can be serious, most are curable with proper diagnosis and effective use of appropriate medications. Life-threatening infections require hospitalization, strong medications, and close monitoring.

Many infections can be diagnosed and treated effectively by primary physicians, but some require the involvement of a specialist in infectious diseases (referred to simply as an infectious disease physician). Infectious disease physicians are first trained and certified in internal medicine or pediatrics and then receive specialized training and certification in infectious diseases.

Infectious disease physicians have in-depth knowledge about the germs that cause infection (even germs imported other countries), how infections develop, and what makes certain germs and infections potentially serious. They are highly skilled in pinpointing the cause of infection and adept at finding clues to a diagnosis from details in a patient's medical history or from results of medical tests. Importantly, they are up to date on the most effective strategies to fight or prevent specific infections. And, unlike specialists who focus on one organ or body system, infectious disease physicians need to know the body from head to toe, since infections can occur anywhere.

Although infectious disease physicians manage all types of infection, their expertise and knowledge are most important when an infection is difficult to diagnose, does not respond well to treatment, is serious (e.g., heart infections [endocarditis, myocarditis], bone and joint infections [osteomyelitis, septic arthritis], nervous system infections [meningitis, encephalitis], HIV infection), or is a major public health threat (e.g., tuberculosis). Infectious disease physicians play an important role in the care of patients who are hospitalized for an infection or who develop infections while hospitalized, and they are often consulted in the care of patients who have health problems that make infection more likely to occur or more difficult to manage. They also provide recommendations to healthy people who plan to travel to areas where the risk of infection is increased.

Infectious Disease Medicine and Chester County Hospital

For more information about infectious disease physicians on the Medical Staff at Chester County Hospital, call our Physician Referral Service at 800-789-PENN (7366) or visit the Find a Doctor section of our website.